Currently, three-dimensional (3D) integrated circuits have been widespread interest from the IC designers, and the 3D integrated circuit can be used to develop a mix IC system with high-density, high flexibility and versatility. Refer to FIG. 1, FIG. 1 illustrates a diagram of a conventional 3D integrated circuit 100 with a vertical through silicon via (TSV). As shown in FIG. 1, TSV 101 and 102 offer a data transmission channel between the chips 103 and 104 in 3D ICs. However, the technology of the TSV suffers from high cost, low reliability, and ESD issues and cause the limitation of the maximum data rate of the 3D integrated circuit.
FIG. 2 illustrates a diagram of a conventional 3D integrated circuit 200 with capacitive sensing. As shown in FIG. 2, chips 203 and 204 in the 3D integrated circuit 200 have capacitive sensing units 2032 and 2034 respectively. Chips 203 and 204 transmit the information via the capacitive sensing units 2032 and 2034. However, capacitive sensing units 2032 and 2034 must be charged by the chips 203 and 204 before the data transmission, thus, the data transmission rate will lower due to the charge process. Thus, the conventional 3D integrated circuits are not a good solution for designers.